LM3478MA_15 Datasheet, PDF (4/26 Pages) Texas Instruments – High-Efficiency Low-Side N-Channel Controller for Switching Regulator

LM3478MA
SNVS705B – FEBRUARY 2011 – REVISED FEBRUARY 2013
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Electrical Characteristics (continued)
Specifications in Standard type face are for T_J = 25°C, and in bold type face apply over the full Operating Temperature
Range. Unless otherwise specified, V_IN = 12V, R_FA = 40kΩ
Symbol
Parameter
Conditions
Typical
Limit
Unit
A_VOL
Error Amplifier Voltage Gain
V_COMP = 1.4V
I_EAO = 100µA (Source/Sink)
38
V/V
26
V/V (min)
44
V/V (max)
I_EAO
Error Amplifier Output Current (Source/ Source, V_COMP = 1.4V, V_FB = 0V
Sink)
110
µA
80/ 50
µA (min)
140/ 180 µA (max)
Sink, V_COMP = 1.4V, V_FB = 1.4V
−140
−100/ −85
−180/ −185
µA
µA (min)
µA (max)
V_EAO
Error Amplifier Output Voltage Swing
Upper Limit
V_FB = 0V
COMP Pin = Floating
2.2
V
1.8
V(min)
2.4
V(max)
Lower Limit
V_FB = 1.4V
0.56
V
0.2
V(min)
1.0
V(max)
T_SS
Internal Soft-Start Delay
T_r
Drive Pin Rise Time
T_f
Drive Pin Fall Time
V_SD
Shutdown threshold ⁽⁶⁾
V_FB = 1.2V, V_COMP = Floating
Cgs = 3000pf, V_DR = 0 to 3V
Cgs = 3000pf, V_DR = 0 to 3V
Output = High
4
msec
25
ns
25
ns
1.27
V
1.4
V (max)
Output = Low
0.65
V
0.3
V (min)
I_SD
Shutdown Pin Current
I_FB
Feedback Pin Current
T_SD
Thermal Shutdown
T_sh
Thermal Shutdown Hysteresis
θ_JA
Thermal Resistance
V_SD = 5V
V_SD = 0V
SOIC-8 Package
−1
µA
+1
15
nA
165
°C
10
°C
151
°C/W
(6) The FA/SD pin should be pulled to V_IN through a resistor to turn the regulator off. The voltage on the FA/SD pin must be above the
maximum limit for Output = High to keep the regulator off and must be below the limit for Output = Low to keep the regulator on.
4
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